Track system for traction of an agricultural vehicle travelling on fields and roads

ABSTRACT

A track system for an agricultural vehicle is configured to better perform when the vehicle is roading, including to reduce or minimize deteriorative effects on a track of the track system as the vehicle travels against a road&#39;s hard surface, especially at higher speeds.

FIELD OF THE INVENTION

The invention relates generally to agricultural vehicles (e.g.,tractors, harvesters, combines, etc.) and, more particularly, to tracksystems for traction of agricultural vehicles.

BACKGROUND

Agricultural vehicles (e.g., tractors, harvesters, combines, etc.)sometimes comprise track systems (instead of tire-equipped wheels) toenhance their traction and floatation in agricultural fields, which maybe soft, slippery, and/or uneven (e.g., soil, mud, etc.).

In addition to travelling in agricultural fields to perform agriculturalwork, agricultural vehicles are often “roading”, i.e., travelling onroads, such as between different fields. When on a road, an agriculturalvehicle's track systems are exposed to conditions that are completelydifferent than those in a field and can drastically affect theirperformance. Notably, the road's hard surface, which may be relativelyhot, and a typical desire of the vehicle's operator to move the vehiclefaster on the road (e.g., to minimize non-productive time out of thefield) may result in severe wear and deterioration of the vehicle'stracks, which may lead to their premature failure.

The applicant has discovered that, under certain operating conditions,an agricultural vehicle's tracks, which have a carcass that isreinforced, can fail very quickly during roading. For instance, trackswith an expected useful life of 2000 or 3000 hours in a fielddeteriorate significantly within merely a few hours of roading. Theeconomic consequences for the vehicle's operator are severe because afailed track, especially one in which the carcass has been damaged,cannot readily be repaired and must typically be replaced.

Without intent of being bound by any particular theory, the actualfailure mechanism of a track's carcass is believed to be essentially asuccession of failures of different components of the track, whichprogressively increases the strain on the carcass until it fails aswell.

To elaborate, as the vehicle is driven on the road, heat buildup startsto develop in the track's tread projections (sometimes referred to as“traction projections”, “traction lugs” or “tread bars”) that projectfrom the track's ground-engaging outer surface. The heat buildup canincrease the internal temperature of a tread projection to a point atwhich the internal elastomeric material outgases, increasing theinternal pressure of the tread projection until it bursts. The effect ofsuch “blowout” is to produce a void volume in the tread projection,which reduces its load carrying capacity. As a result of the voidvolume, the tread projection structurally collapses and loading isdirectly transferred to the carcass underlying the tread projection. Theblowout of multiple traction projections, as shown in FIG. 38, exposesthe carcass in that area of the track to loading that it is not designedto sustain. As shown in FIGS. 39 and 40, the loading can rapidly weardown the carcass and expose its reinforcements, such as its cables,which in turn can wear down causing a complete failure of the track.

Tests performed by the applicant have identified an operational range ofthe vehicle, which is characterized by certain speed, load, and trackwidth factors in which the failure mode occurs almost uncontrollably. Inother words, when the vehicle is roading in that operational range, thecascade of failure events can occur very quickly following an initialblowout event. It is very difficult for the operator to detect theoccurrence of the initial blowout such that even attentive operatorscannot react quickly enough to prevent the track destruction.

The operational range in question tends to be at or beyond theoperational limit of the vehicle, that is, above the manufacturerrecommended maximal speed and maximal weight. Yet it constitutes adesired operational range because the vehicle is the most productive inthose conditions. Accordingly, from an efficiency perspective, operatorstend to operate their vehicles as near as possible to those limits, withthe risk that the track may suffer from a catastrophic failure.

Roading may also cause severe damage to other components of theagricultural vehicle's track systems, including idler wheels (e.g.,front or read idler wheels, or intermediate roller wheels) that contacta track's inner side. For example, this may cause a peripheral coveringof an idler wheel to damage its treaded outer surface, as shown in FIG.41, and/or fail entirely as shown in FIG. 42.

For these and other reasons, there is a need to provide an improvedtrack system for an agricultural vehicle that can notably reduce therisk of failure of its track's carcass when the vehicle is roading, suchas when operated in the above-defined operational range.

SUMMARY OF THE INVENTION

According to various aspects of the invention, a track system fortraction of an agricultural vehicle is configured to better perform whenthe agricultural vehicle is roading, including to reduce or minimizedeteriorative effects on a track of the track system as the agriculturalvehicle travels against a road's hard surface, especially at higherspeeds.

For example, according to an aspect of the invention, there is provideda track system for traction of an agricultural vehicle. The track systemcomprises a track and a track-engaging assembly for driving and guidingthe track around the track-engaging assembly. The track compriseselastomeric material to flex around the track-engaging assembly. Thetrack also comprises a reinforcement within the elastomeric material.The track-engaging assembly comprises a drive wheel for driving thetrack and a plurality of idler wheels for contacting a bottom run of thetrack. The track system comprises an enhanced-roading feature tofacilitate travel of the agriculture vehicle on a road. A speedrestriction for the agricultural vehicle on the road is laxer than ifthe enhanced-roading feature was omitted but the track system wasotherwise identical.

According to another aspect of the invention, there is provided a tracksystem for traction of an agricultural vehicle. The track systemcomprises a track and a track-engaging assembly for driving and guidingthe track around the track-engaging assembly. The track compriseselastomeric material to flex around the track-engaging assembly. Thetrack comprises a reinforcement within the elastomeric material. Thetrack-engaging assembly comprises a drive wheel for driving the trackand a plurality of idler wheels for contacting a bottom run of thetrack. The track system comprises a lateral load distribution mechanismconfigured such that bottom track-contacting areas of laterally-adjacentones of the idler wheels are movable relative to one another in a heightdirection of the track system when the agricultural vehicle travels on aroad. A speed restriction for the agricultural vehicle on the road islaxer than if the bottom track-contacting areas of thelaterally-adjacent ones of the idler wheels were not movable relative toone another in the height direction of the track system when theagricultural vehicle travels on the road but the track system wasotherwise identical.

According to another aspect of the invention, there is provided a tracksystem for traction of an agricultural vehicle. The track systemcomprises a track and a track-engaging assembly for driving and guidingthe track around the track-engaging assembly. The track compriseselastomeric material to flex around the track-engaging assembly. Thetrack comprises a reinforcement within the elastomeric material. Thetrack-engaging assembly comprises a drive wheel for driving the trackand a plurality of idler wheels for contacting a bottom run of thetrack. The track system comprises a lateral load distribution mechanismconfigured such that bottom track-contacting areas of laterally-adjacentones of the idler wheels are movable relative to one another in a heightdirection of the track system when the agricultural vehicle travels on aroad. A speed restriction for the agricultural vehicle on the road isdefined in a zone SRZ indicated in a chart provided in FIG. 43.

According to another aspect of the invention, there is provided a methodfor regulating a speed of an agricultural vehicle on a road. The methodcomprises providing a plurality of track systems for traction of theagricultural vehicle. Each track system comprises a track and atrack-engaging assembly for driving and guiding the track around thetrack-engaging assembly. The track comprises elastomeric material toflex around the track-engaging assembly. The track comprises areinforcement within the elastomeric material. The track-engagingassembly comprises a drive wheel for driving the track and a pluralityof idler wheels for contacting a bottom run of the track. The tracksystem comprises a lateral load distribution mechanism configured suchthat bottom track-contacting areas of laterally-adjacent ones of theidler wheels are movable relative to one another in a height directionof the track system when the agricultural vehicle travels on the road.The method comprises conveying a speed restriction for the agriculturalvehicle on the road that is laxer than if the bottom track-contactingareas of the laterally-adjacent ones of the idler wheels were notmovable relative to one another in the height direction of the tracksystem when the agricultural vehicle travels on the road but the tracksystem was otherwise identical.

According to another aspect of the invention, there is provided a methodfor regulating a speed of an agricultural vehicle on a road. The methodcomprises providing a plurality of track systems for traction of theagricultural vehicle. Each track system comprises a track and atrack-engaging assembly for driving and guiding the track around thetrack-engaging assembly. The track comprises elastomeric material toflex around the track-engaging assembly. The track also comprises areinforcement within the elastomeric material. The track-engagingassembly comprises a drive wheel for driving the track and a pluralityof idler wheels for contacting a bottom run of the track. The methodalso comprises conveying a speed restriction for the agriculturalvehicle on the road. The speed restriction for the agricultural vehicleon the road is defined in a zone SRZ indicated in a chart provided inFIG. 43.

According to another aspect of the invention, there is provided a trackfor traction of an agricultural vehicle. The track is mountable around atrack-engaging assembly for driving and guiding the track. The trackcomprises elastomeric material to flex around the track-engagingassembly. The track comprises a reinforcement within the elastomericmaterial. The track-engaging assembly comprises a drive wheel fordriving the track and a plurality of idler wheels for contacting abottom run of the track. The track comprises a ground-engaging outersurface, an inner surface opposite to the ground-engaging outer surface,and a plurality of traction projections projecting from theground-engaging outer surface. Each traction projection comprises a topsurface for facing the ground. A width of the top surface of thetraction projection is greater than a height of the traction projection.

These and other aspects of the invention will now become apparent tothose of ordinary skill in the art upon review of the followingdescription of embodiments of the invention in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of embodiments of the invention is providedbelow, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 shows an example of an agricultural vehicle comprising a tracksystem in accordance with an embodiment of the invention;

FIGS. 2 and 3 show a perspective view and a side view of the tracksystem;

FIGS. 4 and 5 show a plan view and a side view of a track of the tracksystem;

FIG. 6 shows an inside view of the track;

FIG. 7 shows a cross-sectional view of the track;

FIG. 8 shows a perspective view of a traction projection of the track;

FIG. 9 shows a drive wheel of a track-engaging assembly of the tracksystem;

FIG. 10 shows mid-rollers of the track-engaging assembly engaging aninner side the track;

FIGS. 11 and 12 show perspective views of an idler wheel, and moreparticularly of a mid-roller, of the track-engaging assembly;

FIGS. 13 and 14 show a front view and a side view of the mid-roller;

FIG. 15 shows the idler wheel mounted on its axle via a hub;

FIG. 16 shows a partial cross-sectional side view of a lower portion ofthe track system, including a bogie for mounting the mid-rollers;

FIG. 17 shows a top view of the lower portion of the track system withtwo idler wheels being omitted to show a hub of the idler wheels;

FIG. 18 shows an example of an agricultural vehicle equipped withtypical track systems travelling on a crowned road;

FIG. 19 shows the track system provided herein implementing a lateralload distribution mechanism for evenly distributing a load along awidthwise direction of the track while the agricultural vehicle istravelling on the crowned road;

FIGS. 20 and 21 show an example of an embodiment of the lateral loaddistribution mechanism in which a suspension of the idler wheels isadapted to cause the idler wheels to engage the track evenly along thewidthwise direction of the track while the agricultural vehicle travelsover the crowned road;

FIGS. 22 and 23 respectively show a side view of the suspension of theidler wheels if FIGS. 20 and 21;

FIG. 24 shows an example of an embodiment of the lateral loaddistribution mechanism in which an axle of the idler wheels isaritculated to cause a rotation of a respective idler wheel about anarticulation of the axle;

FIG. 25 shows a side view of the articulation of the axle in a firstconfiguration;

FIG. 26 shows a top view of the articulation of FIG. 25;

FIG. 27 shows a side view of the articulation of the axle in a secondconfiguration;

FIG. 28 shows an example of an embodiment of the lateral loaddistribution mechanism in which the idler wheels are deformable to causethe idler wheels to engage the track evenly along the widthwisedirection of the track while the agricultural vehicle travels over thecrowned road;

FIG. 29 shows the idler wheel of FIG. 28 in a first configuration whenthe agricultural vehicle travels over a flat horizontal surface;

FIG. 30 shows the idler wheel of FIG. 28 in a second configuration whenthe agricultural vehicle travels over the crowned road;

FIG. 31 shows an example of an embodiment of the lateral loaddistribution mechanism in which the bogie of the track system has apitch and roll motion capability to cause the mid-rollers to engage thetrack evenly along the widthwise direction of the track while theagricultural vehicle travels over the crowned road;

FIG. 32 shows the bogie of FIG. 31 including an upper and lower frame ofthe bogie;

FIG. 33 shows a cross-sectional view of the bogie taken along line 33-33as shown in FIG. 32;

FIGS. 34 and 35 show a plan view and a side view of an example of anembodiment of the track in which traction projections of the track havea modified shape and dimensions to minimize deterioration of the track;

FIGS. 36 and 37 show a plan view and a side view of another example ofan embodiment of the track in which the traction projections of thetrack have a modified shape and dimensions to minimize deterioration ofthe track;

FIGS. 38 to 42 show damaged traction projections (i.e., blown out), adamaged carcass having a reinforcement (e.g., cables) exposed, anddamaged idler wheels of a conventional track system as a result ofroading;

FIG. 43 is a chart representing a speed restriction for the agriculturalvehicle on the crowned road as a function of a load on a rear axle ofthe vehicle, and more particularly shows a speed restriction zonecomprising speed restrictions of the vehicle when the agriculturalvehicle has an enhanced-roading feature;

FIGS. 44 to 48 are charts showing examples of speed restriction subzonesfor the agricultural vehicle when the agricultural vehicle travels onthe crowned road;

FIG. 49 is a chart showing a speed restriction for the agriculturalvehicle on the crowned road when the lateral load distribution mechanismallows a roll motion of laterally-adjacent ones of the idler wheels;

FIG. 50 shows an example of an agricultural vehicle comprising two tracksystems rather than four; and

FIG. 51 shows an example of a trailed vehicle configured to be attachedto the agricultural vehicle of FIG. 1 or 50.

It is to be expressly understood that the description and drawings areonly for the purpose of illustrating certain embodiments of theinvention and are an aid for understanding. They are not intended to bea definition of the limits of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows an example of an agricultural vehicle 10 in accordance withan embodiment of the invention. In this embodiment, the agriculturalvehicle 10 is a tractor. In other embodiments, the agricultural vehicle10 may be a combine harvester, another type of harvester, or any othertype of agricultural vehicle.

The agricultural vehicle 10 comprises a frame 12, a powertrain 15, asteering system 17, a plurality of track systems 16 ₁-16 ₄ (which can bereferred to as “undercarriages”), and an operator cabin 20 that enablean operator to move the agricultural vehicle 10 on the ground. Thevehicle 10 can travel in an agricultural field to perform agriculturalwork using a work implement 18. The vehicle 10 can also be “roading”,i.e., travelling on a road (i.e., a paved road having a hard surface ofasphalt, concrete, gravel, or other pavement), such as betweenagricultural fields.

As will be further discussed later, in this embodiment, the tracksystems 16 ₁-16 ₄ of the agricultural vehicle 10 are designed to betterperform when the vehicle 10 is roading, including to reduce or minimizedeteriorative effects on tracks of the track systems 16 ₁-16 ₄ (e.g.,“blowout” of their traction projections, deterioration of their carcass,etc.) as the vehicle 10 travels fast against a road's hard surface.Notably, in this embodiment, each of the track systems 16 ₁-16 ₄ of theagricultural vehicle 10 is designed to better laterally distribute aload it supports onto the road. This may allow the vehicle 10 to travelfaster on the road without excessively wearing or deteriorating thetrack systems 16 ₁-16 ₄, which may make the vehicle 10 more efficientand productive.

The powertrain 15 is configured for generating motive power andtransmitting motive power to the track systems 16 ₁-16 ₄ to propel theagricultural vehicle 10 on the ground. To that end, the powertrain 15comprises a prime mover 14, which is a source of motive power thatcomprises one or more motors. For example, in this embodiment, the primemover 14 comprises an internal combustion engine. In other embodiments,the prime mover 14 may comprise another type of motor (e.g., an electricmotor) or a combination of different types of motor (e.g., an internalcombustion engine and an electric motor). The prime mover 14 is in adriving relationship with the track systems 16 ₁-16 ₄. That is, thepowertrain 15 transmits motive power generated by the prime mover 14 toone or more of the track systems 16 ₁-16 ₄ in order to drive (i.e.,impart motion to) these one or more of the track systems 16 ₁-16 ₄. Thepowertrain 15 may transmit power from the prime mover 14 to the tracksystems 16 ₁-16 ₄ in any suitable way. In this embodiment, thepowertrain 15 comprises a transmission between the prime mover 14 andfinal drive axles 56 ₁, 56 ₂ for transmitting motive power from theprime mover 14 to the track systems 16 ₁-16 ₄. The transmission may bean automatic transmission (e.g., a continuously variable transmission(CVT)) or any other suitable type of transmission.

The work implement 18 is used to perform agricultural work. For example,in some embodiments, the work implement 18 may be a combine head, acutter, a scraper pan, a tool bar, a planter, or any other type ofagricultural work implement.

The operator cabin 20 is where the operator sits and controls theagricultural vehicle 10. More particularly, the operator cabin 20comprises a user interface 70 including a set of controls that allow theoperator to steer the agricultural vehicle 10 on the ground and operatethe work implement 18. For example, in this embodiment, the userinterface 70 comprises an accelerator, a brake control, and a steeringdevice that are operable by the operator to control motion of theagricultural vehicle 10 on the ground and operation of the workimplement 18. The user interface 70 also comprises an instrument panel(e.g., a dashboard) which provides indicators (e.g., a speedometerindicator, a tachometer indicator, etc.) to convey information to theoperator.

The track systems 16 ₁-16 ₄ engage the ground to propel the agriculturalvehicle 10. As shown in FIGS. 2 and 3, each track system 16 _(i)comprises a track-engaging assembly 21 and a track 22 disposed aroundthe track-engaging assembly 21. In this embodiment, the track-engagingassembly 21 comprises a plurality of wheels which, in this example,includes a drive wheel 24 and a plurality of idler wheels that includesfront (i.e., leading) idler wheels 23 ₁, 23 ₂, rear (i.e., trailing)idler wheels 26 ₁, 26 ₂, and roller wheels 28 ₁-28 ₄. The track system16 _(i) also comprises a frame 13 which supports various components ofthe track system 16 _(i), including the idler wheels 23 ₁, 23 ₂, 26 ₁,26 ₂, 28 ₁-28 ₄. The track system 16 _(i) has a longitudinal directionand a first longitudinal end 57 and a second longitudinal end 59 thatdefine a length of the track system 16 _(i) along a longitudinal axis 61that defines the longitudinal direction of the track system 16 _(i). Thetrack system 16 _(i) has a widthwise direction and a width that isdefined by a width W of the track 22. The track system 16 _(i) also hasa height direction that is normal to its longitudinal direction and itswidthwise direction. Each of the front ones of the track systems 16 ₁-16₄ is steerable by the steering system 17 of the agricultural vehicle 10in response to input of the user at the steering device to change anorientation of that track system relative to the frame 12 of theagricultural vehicle 10 in order to steer the agricultural vehicle 10 onthe ground. To that end, each of the front ones of the track systems 16₁-16 ₄ is pivotable about a steering axis 25 of the agricultural vehicle10. An orientation of the longitudinal axis 61 of each of the front onesof the track systems 16 ₁-16 ₄ is thus adjustable relative to alongitudinal axis 97 of the agricultural vehicle 10.

The track 22 engages the ground to provide traction to the agriculturalvehicle 10. A length of the track 22 allows the track 22 to be mountedaround the track-engaging assembly 21. In view of its closedconfiguration without ends that allows it to be disposed and movedaround the track-engaging assembly 21, the track 22 can be referred toas an “endless” track. With additional reference to FIGS. 3 to 6, thetrack 22 comprises an inner side 45, a ground-engaging outer side 47,and lateral edges 49 ₁, 49 ₂. The inner side 45 faces the wheels 23 ₁,23 ₂, 24, 26 ₁, 26 ₂, 28 ₁-28 ₄, while the ground-engaging outer side 47engages the ground. A top run 65 of the track 22 extends between thelongitudinal ends 57, 59 of the track system 16 _(i) and over the wheels23 ₁, 23 ₂, 24, 26 ₁, 26 ₂, 28 ₁-28 ₄, while a bottom run 66 of thetrack 22 extends between the longitudinal ends 57, 59 of the tracksystem 16 _(i) and under the wheels 23 ₁, 23 ₂, 24, 26 ₁, 26 ₂, 28 ₁-28₄. The bottom run 66 of the track 22 defines an area of contact 63 ofthe track 22 with the ground which generates traction and bears amajority of a load on the track system 16 _(i), and which will bereferred to as a “contact patch” of the track 22 with the ground. Thetrack 22 has a longitudinal axis 19 which defines a longitudinaldirection of the track 22 (i.e., a direction generally parallel to itslongitudinal axis) and transversal directions of the track 22 (i.e.,directions transverse to its longitudinal axis), including a widthwisedirection of the track 22 (i.e., a lateral direction generallyperpendicular to its longitudinal axis). The track 22 has a thicknessdirection normal to its longitudinal and widthwise directions.

In this embodiment, the track 22 is relatively narrow. For instance,this may be helpful to allow the track 22 to fit between rows of cropssuch as to leave the crops undisturbed when the agricultural vehicle 10traverses an agricultural field. In turn, this may allow theagricultural field to have a greater crop density. For instance, in someembodiments, a ratio of a width W_(v) of the agricultural vehicle 10(measured between laterally-outwardmost ones of the track systems 16₁-16 ₄) over the width W of the track 22 may be at least 5, in somecases at least 7, in some cases at least 10, in some cases at least 12,and in some cases even more. For example, in some embodiments, the widthW of the track 22 may no more than 30 inches, in some cases no more than25 inches, in some cases no more than 20 inches, in some cases no morethan 18 inches, in some cases no more than 16 inches, and in some caseseven less (e.g., 14.5 inches). The width W of the track 22 may have anyother suitable value in other embodiments.

The track 22 is elastomeric, i.e., comprises elastomeric material, to beflexible around the track-engaging assembly 21. The elastomeric materialof the track 22 can include any polymeric material with suitableelasticity. In this embodiment, the elastomeric material of the track 22includes rubber. Various rubber compounds may be used and, in somecases, different rubber compounds may be present in different areas ofthe track 22. In other embodiments, the elastomeric material of thetrack 22 may include another elastomer in addition to or instead ofrubber (e.g., polyurethane elastomer).

More particularly, the track 22 comprises an endless body 36 underlyingits inner side 45 and ground-engaging outer side 47. In view of itsunderlying nature, the body 36 will be referred to as a “carcass”. Thecarcass 36 is elastomeric in that it comprises elastomeric material 38which allows the carcass 36 to elastically change in shape and thus thetrack 22 to flex as it is in motion around the track-engaging assembly21.

In this embodiment, the carcass 36 comprises a plurality ofreinforcements embedded in its elastomeric material 38. Thesereinforcements can take on various forms.

For example, in this embodiment, the carcass 36 comprises a layer ofreinforcing cables 37 ₁-37 _(M) that are adjacent to one another andextend generally in the longitudinal direction of the track 22 toenhance strength in tension of the track 22 along its longitudinaldirection. In this case, each of the reinforcing cables 37 ₁-37 _(M) isa cord including a plurality of strands (e.g., textile fibers ormetallic wires). In other cases, each of the reinforcing cables 37 ₁-37_(M) may be another type of cable and may be made of any materialsuitably flexible along the cable's longitudinal axis (e.g., fibers orwires of metal, plastic or composite material).

As another example, in this embodiment, the carcass 36 comprises a layerof reinforcing fabric 43. The reinforcing fabric 43 comprises thinpliable material made usually by weaving, felting, knitting,interlacing, or otherwise crossing natural or synthetic elongated fabricelements, such as fibers, filaments, strands and/or others, such thatsome elongated fabric elements extend transversally to the longitudinaldirection of the track 22 to have a reinforcing effect in a transversaldirection of the track 22. For instance, the reinforcing fabric 43 maycomprise a ply of reinforcing woven fibers (e.g., nylon fibers or othersynthetic fibers).

The carcass 36 may be molded into shape in a molding process duringwhich the rubber 38 is cured. For example, in this embodiment, a moldmay be used to consolidate layers of rubber providing the rubber 38 ofthe carcass 36, the reinforcing cables 37 ₁-37 _(M) and the layer ofreinforcing fabric 43.

The inner side 45 of the endless track 22 comprises an inner surface 55of the carcass 36 and a plurality of wheel-contacting projections 48₁-48 _(N) that project from the inner surface 55 and are positioned tocontact at least some of the wheels 23 ₁, 23 ₂, 24, 26 ₁, 26 ₂, 28 ₁-28₄ to do at least one of driving (i.e., imparting motion to) the track 22and guiding the track 22. The wheel-contacting projections 48 ₁-48 _(N)can be referred to as “wheel-contacting lugs”. Furthermore, since eachof them is used to do at least one of driving the track 22 and guidingthe track 22, the wheel-contacting lugs 48 ₁-48 _(N) can be referred toas “drive/guide projections” or “drive/guide lugs”. In some examples ofimplementation, a drive/guide lug 48 _(i) may interact with the drivewheel 24 to drive the track 22, in which case the drive/guide lug 48_(i) is a drive lug. In other examples of implementation, a drive/guidelug 48 _(i) may interact with the front and rear idler wheels 23 ₁, 23₂, 26 ₁, 26 ₂ and/or the roller wheels 28 ₁-28 ₄ to guide the track 22to maintain proper track alignment and prevent de-tracking without beingused to drive the track 22, in which case the drive/guide lug 48 _(i) isa guide lug. In yet other examples of implementation, a drive/guide lug48 _(i) may both (i) interact with the drive wheel 24 to drive the trackand (ii) interact with the idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂ and/orthe roller wheels 28 ₁-28 ₄ to guide the track 22 to maintain propertrack alignment and prevent de-tracking, in which case the drive/guidelug 48 _(i) is both a drive lug and a guide lug.

In this embodiment, the drive/guide lugs 48 ₁-48 _(N) interact with thedrive wheel 24 in order to cause the track 22 to be driven, and alsointeract with the idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂ and the rollerwheels 28 ₁-28 ₄ in order to guide the track 22 as it is driven by thedrive wheel 24 to maintain proper track alignment and preventde-tracking. The drive/guide lugs 48 ₁-48 _(N) are thus used to bothdrive the track 22 and guide the track 22 in this embodiment.

In this example of implementation, the drive/guide lugs 48 ₁-48 _(N) arearranged in a single row disposed longitudinally along the inner side 45of the track 22. The drive/guide lugs 48 ₁-48 _(N) may be arranged inother manners in other examples of implementation (e.g., in a pluralityof rows that are spaced apart along the widthwise direction of the track22).

In this embodiment, each drive/guide lug 48 _(i) is an elastomericdrive/guide lug in that it comprises elastomeric material 67. Theelastomeric material 67 can be any polymeric material with suitableelasticity. More particularly, in this embodiment, the elastomericmaterial 67 includes rubber. Various rubber compounds may be used and,in some cases, different rubber compounds may be present in differentareas of the drive/guide lug 48 _(i). In other embodiments, theelastomeric material 67 may include another elastomer in addition to orinstead of rubber (e.g., polyurethane elastomer). The drive/guide lugs48 ₁-48 _(N) may be provided on the inner side 45 in various ways. Forexample, in this embodiment, the drive/guide lugs 48 ₁-48 _(N) areprovided on the inner side 45 by being molded with the carcass 36.

The ground-engaging outer side 47 comprises a ground-engaging outersurface 31 of the carcass 36 and a tread pattern 40 to enhance tractionon the ground. The tread pattern 40 comprises a plurality of tractionprojections 58 ₁-58 _(T) projecting from the ground-engaging outersurface 31, spaced apart in the longitudinal direction of the endlesstrack 22 and engaging the ground to enhance traction. The tractionprojections 58 ₁-58 _(T) may be referred to as “tread projections” or“traction lugs”.

The traction lugs 58 ₁-58 _(T) may have any suitable shape. In thisembodiment, each of the traction lugs 58 ₁-58 _(T) has an elongatedshape and is angled, i.e., defines an oblique angle θ (i.e., an anglethat is not a right angle or a multiple of a right angle), relative tothe longitudinal direction of the track 22. The traction lugs 58 ₁-58_(T) may have various other shapes in other examples (e.g., curvedshapes, shapes with straight parts and curved parts, etc.).

As shown in FIG. 8, each traction lug 58 _(i) has a periphery 69 whichincludes a front surface 80 ₁, a rear surface 80 ₂, two lateral surfaces81 ₁, 81 ₂, and a top surface 86.

The front surface 80 ₁ and the rear surface 80 ₂ are opposed to oneanother in the longitudinal direction of the track 22. The two lateralfaces 81 ₁, 81 ₂ are opposed to one another in the widthwise directionof the track 22. In this embodiment, the front surface 80 ₁, the rearsurface 80 ₂, and the lateral surfaces 81 ₁, 81 ₂ are substantiallystraight. The periphery 69 of the traction lug 58 _(i) may have anyother shape in other embodiments (e.g., the front surface 80 ₁, the rearsurface 80 ₂, and/or the lateral surfaces 81 ₁, 81 ₂ may be curved). Thetraction lug 58 _(i) has a front-to-rear dimension L_(L) in thelongitudinal direction of the track 22, a side-to-side dimension L_(W)in the widthwise direction of the track 22, and a height H in thethickness direction of the track 22.

In this embodiment, each traction lug 58 _(i) is an elastomeric tractionlug in that it comprises elastomeric material 41. The elastomericmaterial 41 can be any polymeric material with suitable elasticity. Moreparticularly, in this embodiment, the elastomeric material 41 includesrubber. Various rubber compounds may be used and, in some cases,different rubber compounds may be present in different areas of thetraction lug 58 _(i). In other embodiments, the elastomeric material 41may include another elastomer in addition to or instead of rubber (e.g.,polyurethane elastomer). The traction lugs 58 ₁-58 _(T) may be providedon the ground-engaging outer side 47 in various ways. For example, inthis embodiment, the traction lugs 58 ₁-58 _(T) are provided on theground-engaging outer side 47 by being molded with the carcass 36.

The track 22 may be constructed in various other manners in otherembodiments. For example, in some embodiments, the track 22 may haverecesses or holes that interact with the drive wheel 24 in order tocause the track 22 to be driven (e.g., in which case the drive/guidelugs 48 ₁-48 _(N) may be used only to guide the track 22 without beingused to drive the track 22, i.e., they may be “guide lugs” only), and/orthe ground-engaging outer side 47 of the track 22 may comprise variouspatterns of traction lugs.

The drive wheel 24 is rotatable by power derived from the prime mover 14to drive the track 22. That is, power generated by the prime mover 14and delivered over the powertrain 15 of the agricultural vehicle 10 canrotate a final drive axle 56 _(i), which causes rotation of the drivewheel 24, which in turn imparts motion to the track 22.

With additional reference to FIG. 9, in this embodiment, the drive wheel24 comprises a drive sprocket comprising a plurality of drive members 52₁-52 _(B) spaced apart along a circular path to engage the drive/guidelugs 48 ₁-48 _(N) of the track 22 in order to drive the track 22. Thedrive wheel 24 and the track 22 thus implement a “positive drive”arrangement. More particularly, in this embodiment, the drive wheel 24comprises two side discs 50 ₁, 50 ₂ which are co-centric and turn abouta common axle 51 and between which the drive members 52 ₁-52 _(B) extendnear respective peripheries of the side discs 50 ₁, 50 ₂. In thisexample, the drive members 52 ₁-52 _(B) are thus drive bars that extendbetween the side discs 50 ₁, 50 ₂. The drive wheel 24 and the track 22have respective dimensions allowing interlocking of the drive bars 52₁-52 _(B) of the drive wheel 24 and the drive/guide lugs 48 ₁-48 _(N) ofthe track 22. Adjacent ones of the drive bars 52 ₁-52 _(B) define aninterior space 53 between them to receive one of the drive/guide lugs 48₁-48 _(N). Adjacent ones of the drive/guide lugs 48 ₁-48 _(N) define aninter-lug space 39 between them to receive one of the drive bars 52 ₁-52_(B). The drive/guide lugs 48 ₁-48 _(N) and the drive bars 52 ₁-52 _(B)have a regular spacing that allows interlocking of the drive/guide lugs48 ₁-48 _(N) and the drive bars 52 ₁-52 _(B) over a certain length ofthe drive wheel's circumference.

The drive wheel 24 may be configured in various other ways in otherembodiments. For example, in other embodiments, the drive wheel 24 maynot have any side discs such as the side discs 50 ₁, 50 ₂. As anotherexample, in other embodiments, instead of being drive bars, the drivemembers 52 ₁-52 _(B) may be drive teeth that are distributedcircumferentially along the drive wheel 24 or any other type of drivemembers. As another example, in embodiments where the track 22 comprisesrecesses or holes, the drive wheel 24 may have teeth that enter theserecesses or holes in order to drive the track 22. As yet anotherexample, in some embodiments, the drive wheel 24 may frictionally engagethe inner side 45 of the track 22 in order to frictionally drive thetrack 22 (i.e., the drive wheel 24 and the track 22 may implement a“friction drive” arrangement).

The idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ are not driven bypower supplied by the prime mover 14, but are rather used to do at leastone of supporting part of the weight of the agricultural vehicle 10 onthe ground via the track 22, guiding the track 22 as it is driven by thedrive wheel 24, and tensioning the track 22. More particularly, in thisembodiment, the front and rear idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂maintain the track 22 in tension and help to support part of the weightof the agricultural vehicle 10 on the ground via the track 22. As shownin FIG. 10, the roller wheels 28 ₁-28 ₄ roll on a rolling path 33 of theinner side 45 of the track 22 along the bottom run 66 of the track 22 toapply the bottom run 66 on the ground. In this case, as they are locatedbetween frontmost and rearmost ones of the wheels of the track system 16_(i), the roller wheels 28 ₁-28 ₄ can be referred to as “mid-rollers”.

With additional reference to FIGS. 11 to 15, each mid-roller 28 _(i)comprises a hub portion 73, a rim portion 74, and a radially-extendingportion 34 between the hub portion 73 and the rim portion 74. The hubportion 73 is an inner portion of the mid-roller 28 _(i) which isassociated with a hub 75 receiving an axle 76 for the mid-roller 28_(i). The rim portion 74 is an outer portion of the mid-roller 28 _(i)which contacts the inner side 45 of the endless track 22. Theradially-extending portion 34 is an intermediate portion of themid-roller 28 _(i) which extends radially between the hub portion 73 andthe rim portion 74.

The mid-roller 28 _(i) comprises a pair of lateral sides 30 ₁, 30 ₂opposite one another and a peripheral side 32 between the lateral sides30 ₁, 30 ₂. The peripheral side 32 rolls on the inner side 45 of thetrack 22 to apply the bottom run 66 of track 22 on the ground. Moreparticularly, in this embodiment, the mid-roller 28 _(i) rolls on therolling path 33 which is delimited by some of the drive/guide lugs 48₁-48 _(N) such that, as the mid-roller 28 _(i) rolls, these drive/guidelugs pass next to the mid-roller 28 _(i).

In this embodiment, the mid-roller 28 _(i) may engage a significantextent of the width W of the track 22. For example, in some embodiments,a ratio of a width R_(W) of the mid-roller 28 _(i) over the width W ofthe track 22 may be at least 0.2, in some cases at least 0.3, in somecases at least 0.4, and in some cases even more.

In addition, in this embodiment, as shown in FIGS. 16 and 17, the tracksystem 16 _(i) comprises a wheel-mounting subassembly 85 which may bereferred to as a “bogie”. The bogie 85 is configured to carry themid-rollers 28 ₁-28 ₄ and is mounted to the frame 13 of the track system16 _(i). More specifically, the bogie 85 comprises a link 89 to whichare mounted the mid-rollers 28 ₁-28 ₄. The bogie 85 is pivotablerelative to the frame 13 of the track system 16 _(i) about a pivot 87defining an axis of rotation 88 that is perpendicular to thelongitudinal axis 61 of the track system 16 _(i). The bogie 85 thusimparts the mid-rollers 28 ₁-28 ₄ with a pivoting motion capabilitywhich may be referred to as a “pitch” motion. The mid-rollers 28 ₁-28 ₄may not be mounted to a bogie in other embodiments. For example, themid-rollers 28 ₁-28 ₄ may be mounted directly to the frame 13 of thetrack system 16 _(i) in other embodiments.

Moreover, as shown in FIG. 16, the track system 16 _(i) may comprise atensioning mechanism 95 for tensioning the track 22. For instance, inthis embodiment, the tensioning mechanism 95 comprises an actuatormounted at one end to the frame 13 of the track system 16 _(i) and atanother end to a hub of the front idler wheels 23 ₁, 23 ₂. This allowsthe tensioning mechanism 95 to modify a distance between the front idlerwheels 23 ₁, 23 ₂ and the rear idler wheels 26 ₁, 26 ₂ in thelongitudinal direction of the track system 16 _(i).

With additional reference to FIG. 19, in this embodiment, each tracksystem 16 _(i) is designed to better perform when the agriculturalvehicle 10 is roading, i.e., travelling on a road 115, such as betweenagricultural fields, notably by reducing or minimizing deteriorativeeffects on its track 22 (e.g., “blowout” of the traction projections 58₁-58 _(T) of the track 22, deterioration of the carcass 36 of the track22, etc.) as the vehicle 10 travels fast against a hard surface S (e.g.,asphalt, concrete, gravel, or other pavement) of the road 115, therebymaking the vehicle 10 more efficient and productive.

This capability of the track system 16 _(i) to better perform on theroad 115 may be particularly useful in situations such as this examplein which the road's surface S has a cross slope for leading water awayfrom the road 115 (i.e., to avoid water accumulation on the road 115).In this case, the cross slope of the road's surface S is such that theroad 115 has a crown 117, i.e., a highest point, at a center of the road115 in its widthwise direction and slopes downwardly on either side ofthe crown 117. For instance, in some cases, an angle α defined between ahorizontal axis and the road's surface S on either side of the crown 117may be at least 1°, in some cases at least 2°, in some cases at least4°, and in some cases even higher (e.g., at least 6° or 8°). The angle αmay have any other value in other cases. In view of its crown 117, theroad 115 may sometimes be referred to as a “crowned road”.

In this embodiment, the track system 16 _(i) may be configured toaccommodate a shape of the road 115, including its crown 117 in thisexample, so as to better distribute loading on its track 22 than aconventional track system. For example, with additional reference toFIG. 18, an agricultural vehicle 800 equipped with conventional tracksystems 816 ₁-816 ₄ may perform poorly while travelling on the crownedroad 115. Notably, a track 822 of a track system 816 i may have alateral extent of its contact patch 863 with the crowned road 115 thatis significantly reduced. This can adversely affect traction of thetrack 822 on the road 115, but, more importantly, generates significantloads on the track 822 that result in severe stress regions which canaccelerate wear and deterioration of the track 822 and lead to prematurefailure of the track 822. This problem may be amplified when theagricultural vehicle 800 is roading at elevated speeds.

The track system 16 _(i) may have various features to better performwhen the agricultural vehicle 10 is travelling on the road 115. Examplesof these “enhanced-roading features” are discussed below.

1. Lateral Load Distribution Mechanism

In some embodiments, with additional reference to FIG. 19, the tracksystem 16 _(i) may comprise a lateral load distribution mechanism 100configured to increase a lateral extent C of the contact patch 63 of thetrack 22 when the agricultural vehicle 10 travels on the crowned road11. This may reduce peak loads experienced by the track 22 and thus helpto reduce potential for rapid wear or other deterioration of the track22 as the vehicle 10 travels on the road's hard surface S, particularlyat high speed.

In this embodiment, the lateral load distribution mechanism 100 isconfigured to apply the idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄onto the bottom run 66 of the track 22 such as to increase the lateralextent C of the contact patch 63 of the track 22 when the agriculturalvehicle 10 is travelling on the road's surface S which has the crossslope in a direction normal to a direction of travel of the agriculturalvehicle 10. For example, in some embodiments, the lateral loaddistribution mechanism 100 may be configured to apply laterally-adjacentones of the idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ onto thebottom run 66 of the track 22 to increase the lateral extent C of thecontact patch 63 of the track 22. The laterally-adjacent ones of theidler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ are respective ones ofthese wheels that are generally aligned with respect to one another orotherwise closest to one another in the longitudinal direction of thetrack system 16 _(i) (e.g., the front idler wheels 23 ₁, 23 ₂, and/orthe rear idler wheels 26 ₁, 26 ₂, and/or the mid-rollers 28 ₁, 28 ₃,and/or the mid-rollers 28 ₂, 28 ₄).

The lateral load distribution mechanism 100 may be configured such thatbottom track-contacting areas 146 of laterally-adjacent ones of theidler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ are vertically movablerelative to one another (i.e., movable relative to one another in theheight direction of the track system 16 _(i)). The bottomtrack-contacting area 146 of a given one of the idler wheels 23 ₁, 23 ₂,26 ₁, 26 ₂, 28 ₁-28 ₄ is that area of the given one of the idler wheels23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ which contacts the bottom run 65 ofthe track 22.

For instance, in this embodiment, the lateral load distributionmechanism 100 may increase the lateral extent C of the contact patch 63of the track 22 when the agricultural vehicle 10 travels on the crownedroad 115 such that a ratio of the lateral extent C of the contact patch63 of the track 22 over the width W of the track 22 is at least 0.3, insome cases at least 0.4, in some cases at least 0.5, in some cases atleast 0.6, and in some cases even more (e.g., at least 0.8). In somecases, the lateral load distribution mechanism 100 may cause the lateralextent C of the contact patch 63 to correspond to an entirety of thewidth W of the track 22.

As a result of the increased lateral extent C of the contact patch 63 ofthe track 22 provided by the lateral load distribution mechanism 100, apeak load exerted on the track 22 on the road 115 may be reduced. Forinstance, in some embodiments, a ratio of the peak load exerted on thetrack 22 over a load on the track system 16 _(i) on the road 115 (i.e.,calculated by dividing the weight of the vehicle 10 by the number oftrack systems 16 ₁-16 ₄) may be no more than a certain value. [. Forexample, in some embodiments, the peak load exerted on the track 22 onthe road 115 may be no more than a certain value.

The lateral load distribution mechanism 100 may be implemented invarious ways, certain examples of which will be described below.

1.1 Idler Wheel Roll Motion

In some embodiments, the lateral load distribution mechanism 100 mayallow a “roll” motion of respective ones of the front and rear idlerwheels 23 ₁, 23 ₂, 26 ₁, 26 ₂ and/or the mid-rollers 28 ₁-28 ₄. That is,the lateral load distribution mechanism 100 may be configured to allow amotion of respective ones of the front and rear idler wheels 23 ₁, 23 ₂,26 ₁, 26 ₂ and/or the mid-rollers 28 ₁-28 ₄ relative to the frame 12 ofthe agricultural vehicle 10 that includes a rotation about a roll axis164 which is transverse to their axes of rotation, in this case,parallel to the longitudinal axis 61 of the track system 16 _(i).

For example, in some embodiments, the roll motion enabled by the lateralload distribution mechanism 100 may be implemented by the bogie 85. Morespecifically, the bogie 85 may be movable relative to the frame 12 ofthe vehicle 10 to cause the front and rear idler wheels 23 ₁, 23 ₂, 26₁, 26 ₂ and/or the mid-rollers 28 ₁-28 ₄ to rotate about the roll axis164 as they engage the bottom run 66 of the track 22 when theagricultural vehicle 10 travels on the crowned road 115.

More particularly, in some embodiments, as shown in FIG. 31, the bogie85 is configured to define the roll motion and a “pitch” motion ofrespective ones of the mid-rollers 28 ₁-28 ₄. That is, the bogie 85 candefine a rotation about the roll axis 164 parallel to the longitudinalaxis 61 of the track system 16 _(i) and about a pitch axis 174 parallelto the widthwise direction of the track system 16 _(i).

As shown in FIGS. 32 and 33, in this embodiment, the bogie 85 comprisesan upper structure 152 and a lower structure 154 connected to the upperstructure 154. The lower structure 154 is configured to provide thebogie 85 with its roll motion capability. The lower structure 154comprises a pair of axle-retaining members 156 ₁, 156 ₂ spaced apart inthe longitudinal direction of the track system 16 _(i), and a rollmotion mechanism 158 connecting the axle-retaining members 156 ₁, 156 ₂to one another. The axle-retaining members 156 ₁, 156 ₂ are configuredto receive the axles 76 of the mid-rollers 28 ₁-28 ₄ (e.g., via a holetraversing each axle-retaining member 156 _(i)). Each axle 76 receivestwo laterally adjacent mid-rollers 28 _(i), 28 _(j) thereon.

The roll motion mechanism 158 comprises a shaft 160 and an outer tube162 receiving the shaft 160 therein. The shaft 160 extends in thelongitudinal direction of the track system 16 i and is connectable tothe axle-retaining members 156 ₁, 156 ₂. For example, the shaft 160 maybe connected to the axle-retaining members 156 ₁, 156 ₂ via aninterference fit. In other embodiments, the shaft 160 may be connectedto the axle-retaining members 156 ₁, 156 ₂ in any other suitable way(e.g., via welding, fasteners, etc.). The outer tube 162 is mounted tothe shaft 160 and extends between the axle-retaining members 156 ₁, 156₂. The shaft 160 is rotatable within the outer tube 162 about an axis ofrotation of the outer tube 162 which corresponds to the roll axis 164.In this embodiment, the shaft 160 rotates within the outer tube 162 viaa bearing 166 (e.g., a roller bearing) disposed between a peripheralsurface of the shaft 160 and an inner surface of the outer tube 162. Theshaft 160 may rotate within the outer tube 162 via any other suitablemechanism in other embodiments.

The upper structure 152 of the bogie 85 is configured to provide thebogie 85 with its pitch motion capability. The upper structure 152comprises a body 168 affixed to the lower structure 154 (e.g., viawelding). The body 168 comprises a shaft-receiving aperture 170 forreceiving therein a shaft 172. The shaft 172 is rotatable within theshaft-receiving aperture 170 about an axis of rotation that correspondsto the pitch axis 174. For example, the shaft-receiving aperture 170 maycomprise a bearing 176 (e.g., a roller bearing) for enabling rotation ofthe shaft 172 within the shaft-receiving aperture 170. As shown in FIG.33, the shaft 170 is connected at its longitudinal end portions to theframe 13 of the track system 16 _(i) which supports the bogie 85.

Thus, in this embodiment, the lateral load distribution mechanism 100allows the bogie 85 to define the roll motion and the pitch motion aboutthe roll and pitch axes 164, 174 respectively. Therefore, when theagricultural vehicle 10 travels on the crowned road 115, the bogie 85allows the mid-rollers 28 ₁-28 ₄ to pivot about the roll axis 164causing the mid-rollers 28 ₁-28 ₄ to apply the bottom run 66 of thetrack 22 more evenly on the hard surface S of the crowned road 115.

The roll motion of respective ones of the front and rear idler wheels 23₁, 23 ₂, 26 ₁, 26 ₂ and/or the mid-rollers 28 ₁-28 ₄ may be implementedby the lateral load distribution mechanism 100 in any other suitable wayin other embodiments.

1.2 Adaptable Idler Wheel Suspension

In some embodiments, the lateral load distribution mechanism 100 mayimplement an adaptable suspension of respective ones of the idler wheels23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄. For instance, the lateral loaddistribution mechanism 100 may cause a suspension of the front and rearidler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂ and/or a suspension of themid-rollers 28 ₁-28 ₄ to increase the lateral extent C of the contactpatch 63 of the track 22 when the agricultural vehicle 10 travels on thecrowned road 115.

For example, in some embodiments, as shown in FIG. 20, the lateral loaddistribution mechanism 100 may comprise a suspension oflaterally-adjacent mid-rollers 28 _(i), 28 _(j) which comprises axles110 ₁, 110 ₂ that are moveable with respect to one another and aboutwhich the mid-rollers 28 _(i), 28 _(j) are rotatable. For example, eachaxle 110 _(i) may be received within the hub 75 (shown in FIG. 15) whichrotates relative to the axle 110 _(i) about an axis of rotation 116. Thesuspension of the lateral load distribution mechanism 100 thuseffectively implements an independent suspension for thelaterally-adjacent mid-rollers 28 _(i), 28 _(j) that allows them to moveindependently from one another in the height direction of the tracksystem.

In this example, the suspension of the lateral load distributionmechanism 100 also comprises a resilient member 111 mounted between theaxles 110 ₁, 110 ₂, and a frame 114. The resilient member 111 isconfigured to change in configuration from a first configuration to asecond configuration in response to a load and recover the firstconfiguration in response to removal of the load in order to allowrelative movement of the axles 110 ₁, 110 ₂. In this embodiment, theresilient member 111 comprises a pair of resilient elements 112 ₁, 112₂. Each resilient element 112; is mounted at one end to the axle 110_(i) and at another end to the frame 114 in order to allow the axle 110_(i) to move relative to the frame 114 in the height direction of thetrack system 16 _(i). The resilient member 112 _(i) comprises a spring113. The spring 113 may be a coil spring, a torsion spring, a leafspring, an elastomeric spring (e.g., a rubber spring), a fluid spring(e.g., an air spring), or any other object that is operable to change inconfiguration from a first configuration to a second configuration inresponse to a load and recover the first configuration in response toremoval of the load.

As shown in FIGS. 22 and 23, the frame 114 is configured to support theaxle 110 _(i) and to bound its motion. For instance, in this embodiment,the frame 114 comprises a slot 118 generally extending in the heightdirection of the track system 16 and along which the axle 110 _(i) ismovable. In this embodiment, the frame 114 is a part of the bogie 85. Inother embodiments, the frame 114 may be part of the frame 13 of thetrack system 16 _(i).

Thus, each resilient element 112 _(i) exerts a downward force on acorresponding axle 110 _(i) to cause the corresponding mid-roller 28_(i) to apply the bottom run 66 of the track 22 onto the ground.Moreover, motion of the axle 110 _(i) is limited both in the heightdirection and in the longitudinal direction of the track system 16 _(i)by the frame 114.

Therefore, when the agricultural vehicle 10 travels on the crowned road115, as illustrated in FIG. 21, the lateral load distribution system 100causes the mid-roller 28 _(i) that is at a lowest section of the road tobe moved lower in the height direction of the track system 16 _(i) whilethe other mid-roller 28 that is at a highest section of the road ismoved higher in the height direction of the track system 16 _(i). Thismay help to more evenly apply the bottom run 66 of the track 22 onto thehard surface S of the crowned road 115 such as to increase the lateralextent C of the contact patch 63 of the track 22.

Although the lateral load distribution mechanism 100 has been describedin respect of laterally-adjacent mid-rollers 28 _(i), 28 _(j), a similarsystem may be applied to other laterally-adjacent idler wheels such asthe front idler wheels 23 ₁, 23 ₂ and the rear idler wheels 26 ₁, 26 ₂.For example, the front idler wheels 23 ₁, 23 ₂ may rotate about separateaxles that are adaptably supported by the frame 13 of the track system16 _(i) such that a height of each separate axle is varied when theagricultural vehicle 10 travels on the crowned road 115.

The suspension of respective ones of the idler wheels 23 ₁, 23 ₂, 26 ₁,26 ₂, 28 ₁-28 ₄ may be implemented by the lateral load distributionmechanism 100 in any other suitable way in other embodiments.

1.3 Articulated Idler Wheel Axle

In some embodiments, the lateral load distribution mechanism 100 mayimplement an articulated axle of one or more of the idler wheels 23 ₁,23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ that causes the front and rear idler wheels23 ₁, 23 ₂, 26 ₁, 26 ₂ and/or the mid-rollers 28 ₁-28 ₄ to engage thetrack 22 in order to increase the lateral extent C of the contact patch63 of the track 22 when the agricultural vehicle 10 travels on thecrowned road's surface S.

For example, in some embodiments, as shown in FIGS. 24 to 27, thelateral load distribution mechanism 100 may comprise articulated axles119 ₁, 119 ₂ for laterally-adjacent mid-rollers 28 _(i), 28 _(j). Eacharticulated axle 119 _(x) comprises an articulation 124 _(x) betweensections 121 ₁, 121 ₂ of the articulated axle 119 _(i) to allow thesections 121 ₁, 121 ₂ of the articulated axle 119 _(x) to move relativeto one another to accommodate the crowned road's surface S.

In this embodiment, the articulated axles 119 ₁, 119 ₂ are part of acommon axle 120. The outboard section 121 ₁ of each articulated axle 119_(x) comprises a spindle 122 leading to the mid-rollers 28 _(x) whilethe inboard section 121 ₂ of the articulated axle 119 _(x) comprises acentral portion 123 of the common axle 120. The articulation 124 _(x)constitutes a joint between the spindle 122 and the central portion 123of the common axle 120. In other embodiments, the articulated axles 119₁. 119 ₂ may be separate from one another (i.e., not part of any commonaxle).

More particularly, in this embodiment, the common axle 120 comprises ashaft extending along a longitudinal axis 125 (generally parallel to thewidthwise direction of the track system 16 _(i)) and mounted to a frame126. In this example, the frame 126 is part of the bogie 85. However, inother examples, the frame 126 may be a part of the frame 13 of the tracksystem 16 _(i). The central portion 123 of the common axle 120 comprisesa first connecting portion 128 at each end portion of the centralportion 123. In this embodiment, the first connecting portion 128comprises a forked connector including two prongs extending along thelongitudinal axis 125.

The spindle 122 of each articulated axle 119 _(x) is configured formounting a respective mid-roller 28 _(i) and comprises a shaft extendingalong a longitudinal axis 127 of the spindle 122. For example, themid-roller 28 _(i) may be mounted to the spindle 122 via the hub 75 aspreviously described and illustrated in FIG. 15. The spindle 122comprises a second connecting portion 130 at a longitudinal end thereof.The second connecting 130 of the spindle 122 is complimentary to thefirst connecting portion 128 of the central portion 123 of the commonaxle 120. For example, in this embodiment, the second connecting portion130 comprises a single-pronged connector extending in a longitudinaldirection of the spindle 122.

The articulation 124 _(x) allows the spindle 122 to move relative to thecentral portion 123 of the common axle 120 such that the longitudinalaxis 127 of the spindle 122 is movable relative to the longitudinal axis125 of the common axle 120. More specifically, the articulation 124 _(x)defines an axis of rotation 132 about which the spindle 122 isrotatable. The axis of rotation 132 of the articulation 124 _(x) isdefined by a rotation member 134 which rotatably connects the first andsecond connecting portions 128, 130 to one another. In this embodiment,the rotation member 134 comprises a dowel pin which may be secured tothe first and second connecting portions 128, 130 in any suitable way(e.g., via cotter pins).

In this embodiment, the articulation 124, further comprises a resilientelement 136 for biasing the spindle 122 to rotate about the axis ofrotation 132 in a particular direction. More specifically, the resilientelement 136 urges the spindle 122 to rotate downwardly (i.e., towardsthe bottom run 66 of the track 22). The resilient element 136 comprisesa spring 137. In this embodiment, the spring 137 comprises a torsionspring. The spring 137 may be a coil spring, a leaf spring, anelastomeric spring (e.g., a rubber spring), a fluid spring (e.g., an airspring), or any other object that is operable to change in configurationfrom a first configuration to a second configuration in response to aload and recover the first configuration in response to removal of theload in other embodiments.

In some embodiments, the resilient element 136 may be omitted as theweight of the mid-roller 28 _(i) may be sufficient to cause the spindle122 _(i) to rotate downwardly.

In use, as shown in FIGS. 24 and 27, when the agricultural vehicle 10travels on the crowned road 115, the lateral load distribution mechanism100 causes the spindle 122 that is at a lowest section of the road 115to be rotated downwardly (i.e., towards the bottom run 66 of the track22) and the spindle 122 that is at a highest section of the road 115 tobe rotated upwardly (i.e., towards the upper run 65 of the track 22). Asa result, the mid-roller 28 _(i) that is at the lowest section of theroad 115 is moved lower in the height direction of the track system 16_(i) while the other mid-roller 28 _(j) that is at the highest sectionof the road 115 is moved higher in the height direction of the tracksystem 16 _(i). This may more evenly apply the bottom run 66 of thetrack 22 onto the hard surface S of the crowned road 115 such as toincrease the lateral extent C of the contact patch 63 of the track 22.

Although the lateral load distribution mechanism 100 has been describedin respect of laterally adjacent mid-rollers 28 _(i), 28 _(j), a similarsystem may be applied to other laterally-adjacent idler wheels such asthe front idler wheels 23 ₁, 23 ₂ and the rear idler wheels 26 ₁, 26 ₂.

The articulated axles of respective ones of the idler wheels 23 ₁, 23 ₂,26 ₁, 26 ₂, 28 ₁-28 ₄ may be implemented by the lateral loaddistribution mechanism 100 in any other suitable way in otherembodiments (e.g., a spherical joint, a universal joint, etc.).

1.4 Deformable Idler Wheels

In some embodiments, the lateral load distribution mechanism 100 may beimplemented by deformation (i.e., change in configuration) of one ormore of the idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄. Forinstance, as shown in FIG. 28, the lateral load distribution system 100may allow deformation of the front and rear idler wheels 23 ₁, 23 ₂, 26₁, 26 ₂ and/or the mid-rollers 28 ₁-28 ₄ to engage the track 22 tominimize a decrease in the lateral extent C of the contact patch 63 ofthe track 22 when the agricultural vehicle 10 travels over the crownedroad surface S.

More particularly, the lateral load distribution mechanism 100 may allowthe front and rear idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂ and/or themid-rollers 28 ₁-28 ₄ to deform from a first configuration to a secondconfiguration to cause the bottom run 66 of the track 22 to be appliedonto the ground when the agricultural vehicle 10 travels over thecrowned road surface S.

For example, in some embodiments, as shown in FIG. 29, each mid-roller28 _(i) may comprise a wheel body 60 and a covering 62 (e.g., a tire)disposed over the wheel body 60.

The wheel body 60 is a core of the mid-roller 28 ₁ that impartsstructural integrity to the mid-roller 28 _(i). The wheel body 60 has apair of lateral sides opposite one another and a peripheral side 77between the lateral sides. In this case, the lateral sides of the wheelbody 60 form part of the lateral sides 30 ₁, 30 ₂ of the mid-roller 28_(i), while the peripheral side 65 of the wheel body 60 is covered bythe covering 62. The wheel body 60 defines an internal space 68delimited by internal surfaces of the wheel body 60. The internal space68 includes an internal circumferential channel 66 which is defined by ashoulder 71 of the wheel body 60. Moreover, the wheel body 60 comprisesan opening 72 that is accessible from the internal space 68 of the wheelbody 60 and grants access to the deformable member 64.

In this case, the hub 75 is removably mounted to the wheel body 60. Moreparticularly, in this case, a hub portion of the wheel body 60,corresponding to the hub portion 73 of the mid-roller 28 _(i), comprisesa plurality of openings in which are received a plurality of fastenersthat interconnect the wheel body 60 to the hub 75. The hub portion ofthe wheel body 60 may be configured in various other ways in otherembodiments (e.g., the hub 75 may be integrally formed (e.g., cast) withor permanently affixed (e.g., welded) to the hub portion of the wheelbody 60).

The wheel body 60 is made of at least one material, referred to as“wheel body material”. That is, the wheel body 60 comprises one or morewheel body materials making up the wheel body 60. In some cases, thewheel body 60 may comprise a single wheel body material making up anentirety of the wheel body 60. In other cases, the wheel body 60 maycomprise two or more wheel body materials that make up different partsof the wheel body 60.

In this embodiment, the wheel body 60 is a metallic wheel body. Thewheel body 60 is metallic in that it is at least mainly (i.e., it ismostly or entirely) made of a metallic material. The metallic materialis selected to provide strength and rigidity to the mid-roller 28 _(i).For example, in this case, the metallic material comprises steel. Inother cases, the metallic material may comprise another metal instead ofsteel. In other embodiments, the wheel body 60 may be at least mainlymade of another type of material (e.g., composite material, polymericmaterial, or ceramic material). Also, in other embodiments, differentparts of the wheel body 60 may be made of two or more wheel bodymaterials (e.g., two types of steel).

The covering 62 contacts the inner side 45 of the endless track 22 asthe mid-roller 28 _(i) rolls on the inner side 45 of the track 22. Inthis embodiment, the covering 62 forms at least part of the peripheralside 32 and at least part of at least one of the lateral sides 30 ₁, 30₂ of the mid-roller 28 _(i). More particularly, in this embodiment, thecovering 62 comprises a peripheral portion 78 that forms the peripheralside 32 of the mid-roller 28 _(i) and a lateral portion 82 that formspart of the lateral side 30 ₂ of the mid-roller 28 _(i) which faces adrive/guide lug 48 _(i).

The covering 62 covers at least part of the wheel body 60 of themid-roller 28 _(i). In this embodiment, the covering 62 covers theperipheral side 77 of the wheel body 60 and part of a lateral side ofthe wheel body 60. Notably, the covering 62 covers at least part, inthis case all, of an external surface of the shoulder 76 of the wheelbody 60.

The covering 62 is made of at least one material, referred to as a“covering material”. That is, the covering 62 comprises one or morecovering materials making up the covering 62. In some cases, thecovering 62 may comprise a single covering material making up anentirety of the covering 62. In other cases, the covering 62 maycomprise two or more covering materials that make up different parts ofthe covering 62.

The covering material of the covering 62 is different from a wheel bodymaterial of the wheel body 60. That is, the covering material and thewheel body material may belong to different classes of materials (i.e.,metals, polymers, ceramics and composites) and/or may substantiallydiffer in terms of one or more properties, such as strength, elasticity,hardness, friction coefficient, etc. For instance, in some cases: astrength (e.g., yield strength) of the wheel body material may bedifferent from (e.g., greater than) a strength of the covering material;a modulus of elasticity of the covering material may be different from(e.g., less than) a modulus of elasticity of the wheel body material; anabrasion resistance of the covering material may be different from(e.g., greater than) an abrasion resistance of the wheel body material;a coefficient of friction of the covering material with the track 22 maybe different from (e.g., less than) a coefficient of friction of thewheel body material with the track 22; etc.

In this embodiment, the modulus of elasticity of the covering materialof the wheel covering 62 is substantially lower than a modulus ofelasticity of the elastomeric material of the track 22. For instance, aratio of the modulus of elasticity of the covering material over themodulus of elasticity of the elastomeric material of the track 22 may beat most 0.6, in some cases at most 0.5, in some cases at most 0.4, insome cases at most 0.3, and in some cases even less.

As shown in FIG. 29, when the agricultural vehicle 10 travels over asubstantially flat terrain, the mid-roller 28 _(i) assumes its firstconfiguration in which the peripheral portion 78 of the covering 62 issubstantially parallel to the peripheral side 77 of the wheel body 60.

As shown in FIG. 30, when the agricultural vehicle 10 travels over thecrowned road surface S, the mid-roller 28 _(i) assumes its secondconfiguration. More specifically, the covering 62 of the mid-roller 28_(i) deforms such that a lower portion of its peripheral portion 78 istransverse (i.e., nonparallel) to the peripheral side 77 of the wheelbody 60. Thus, the peripheral portion 78 of the covering 62 defines anangle φ between an outer surface of its peripheral portion 78 and anouter surface of the peripheral side 77 of the wheel body 60. Forinstance, the angle φ may be at least 1°, in some cases at least 2°, insome cases at least 3°, in some cases at least 4°, in some cases atleast 5°, and in some cases even greater (e.g., 6°). For example, insome cases, the angle φ may be equal to the angle α defined by thesloped surface S of the crowned road 115.

Thus, in use, when the agricultural vehicle 10 travels over the crownedroad 115, the covering 62 of the mid-roller 28 _(i) elastically deformssuch that the lower portion of the peripheral portion 78 (i.e., theportion in contact with the bottom run 66 of the track 22) defines theangle φ relative to the peripheral side 77 of the wheel body 60. Thismay minimize a reduction in the lateral extent C of the contact patch 63of the track 22 that would otherwise occur if the lateral loaddistribution mechanism 100 were not implemented.

Although the lateral load distribution mechanism 100 has been describedin respect of laterally adjacent mid-rollers 28 _(i), 28 _(j), a similarsystem may be applied to other laterally adjacent idler wheels such asthe front idler wheels 23 ₁, 23 ₂ and the rear idler wheels 26 ₁, 26 ₂.

The deformation of one or more of the idler wheels 23 ₁, 23 ₂, 26 ₁, 26₂, 28 ₁-28 ₄ allowed by the lateral load distribution mechanism 100 maybe implemented in any other suitable way in other embodiments (e.g., thecovering 62 may comprise a “balloon” tire (i.e., a low-pressure tire) ora bladder containing a fluid that can deform to accommodate the crownedroad's hard surface S).

2. Wider and/or Shorter Traction Lugs

In some embodiments, the track 22 of the track system 16 _(i) may beconfigured to be more resistant to wear as the agricultural vehicle 10is roading. For instance, in some embodiments, the tread pattern 40 ofthe track 22 may be more resistant to wear or other deterioration as theagricultural vehicle 10 travels on the road's hard surface S. Notably,the tread pattern 40 of the track 22 may be designed to reduce potentialfor blowout of the traction lugs 58 ₁-58 _(T) by reducing heat buildupwithin the track 22.

To that end, in some embodiments, as shown in FIGS. 34 and 35, thetraction lugs 58 ₁-58 _(T) may be dimensioned to reduce potential forheat buildup within them and to facilitate their internal heatdissipation. For example, a ground-contacting area of each traction lug58 _(i) may be increased and/or the height H of the traction lug 58 _(i)may be decreased in order to reduce deformation of the tractionprojection 58 _(i) as it repeatedly contacts the road's hard surface Sas the agricultural vehicle 10 is roading. Increasing theground-contacting area of the traction lug 58 _(i) distributes loadingon the traction lug 58 _(i) over a larger space and may thus reducestress and strain of the traction lug 58 _(i). Decreasing the height Hof the traction lug 58 _(i) may also help to reduce deflection of thetraction lug 58 _(i). This reduced deformation of the traction lug 58_(i) as it frequently engages the road's surface S while the vehicle 10is roading may help to reduce heat buildup within the traction lug 58_(i), thus reducing potential for blowout of the traction lug 58 _(i).In other words, by “flattening” the traction lug 58 _(i), it may deformless and thus be less susceptible to blowout.

For example, in some embodiments, the width L_(W) of the traction lug 58_(i) may be greater than that of conventional tracks. For instance, thewidth L_(W) of the top surface 86 of the traction lug 58 _(i) may beincreased in relation to the width W of the track 22. For instance, aratio of the width L_(W) of the traction lug 58 _(i) over the width W ofthe track 22 may be at least 0.5, in some cases at least 0.6, in somecases at least 0.7, and in some cases even more. The ratio of the widthL_(W) of the traction lug 58 _(i) over the width W of the track 22 mayhave any other suitable value in other embodiments.

In some embodiments, a width TS of the top surface 86 of the tractionlug 58 _(i) may be significantly greater than that of conventionaltracks. For instance, the width TS of the top surface 86 of the tractionlug 58 _(i) may be increased in relation to the width W of the track 22.For example, a ratio of the width TS of the top surface 86 of thetraction lug 58 _(i) over the width W of the track 22 may be at least0.1, in some cases at least 0.15, in some cases at least 0.2, and insome cases even more. The ratio of the width TS of the top surface 86 ofthe traction lug 58 _(i) over the width W of the track 22 may have anyother suitable value in other embodiments.

Furthermore, the height H of the traction lug 58 _(i) may beconsiderably smaller than that of conventional tracks. For instance, aratio of the height H of the traction lug 58 _(i) over the thicknessT_(C) of the carcass 36 may be no more than 1.2, in some cases no morethan 1.15, in some cases no more than 1.1, in some cases no more than1.05, and in some cases even less. The ratio of the height H of thetraction lug 58 _(i) over the thickness T_(C) of the carcass 36 may haveany other suitable value in other embodiments.

In some embodiments, a ratio of the width TS of the top surface 86 ofthe traction lug 58 _(i) over the height H of the traction lug lug 58_(i) may be greater than conventional tracks. For example, in someembodiments, the ratio of the width TS of the top surface 86 of thetraction lug 58 _(i) over the height H of the traction lug lug 58 _(i)may be greater than one, in some cases at least 1.2, in some cases atleast 1.4, in some cases at least 1.6, in some cases at least 1.8, andin some cases even more (e.g., 2 or more). The ratio of the width TS ofthe top surface 86 of the traction lug lug 58 _(i) over the height H ofthe traction lug 58 _(i) may have any other suitable value in otherembodiments.

In this embodiment, with its track systems 16 ₁-16 ₄ designed to betterperform when it is roading, the agricultural vehicle 10 may travelfaster on the road 115 without excessively wearing or deteriorating thetrack systems 16 ₁-16 ₄.

For example, in some embodiments, a speed restriction for theagricultural vehicle 10 on the road 115 may be laxer (i.e., lessstringent) than if an enhanced-roading feature (e.g., the lateral loaddistribution mechanism 100 or the wider and/or shorter traction lugs 58₁-58 _(T)) of a track system 16 _(i) was omitted but the track system 16_(i) was otherwise identical. That is, the agricultural vehicle 10 maybe authorized to travel faster on the road 115 than if theenhanced-roading feature of the track system 16 _(i) was omitted but thetrack system 16 _(i) was otherwise identical.

The speed restriction for the agricultural vehicle 10 on the road 115may be conveyed by a provider of the track system 16 _(i) as arecommended maximal speed of the agricultural vehicle 10 on the road 115in certain conditions, including a load on an axle of the vehicle 10that carries the track system 16 _(i). For example, the provider of thetrack system 16 _(i) may be a manufacturer of the track system 16 _(i)and/or a manufacturer of the agricultural vehicle 10 (e.g., an originalequipment manufacturer (OEM)).

For instance, in some embodiments, as shown in a chart represented inFIG. 43, the speed restriction for the agricultural vehicle 10 on theroad 115 may be expressed as a recommended maximal speed of the vehicle10 as a function of a load on an axle of the vehicle 10 carrying thetrack system 16 _(i). In this example, the axle is a rear axle of thevehicle 10 (e.g., as the load on the rear axle of the vehicle 10 may begreater when the work implement 18 is mounted to a rear portion of thevehicle 10). Also, in this example, the track 22 is narrow. Moreparticularly, in this example, the width W of the track 22 is 18 inches.Furthermore, in this example, the speed restriction for the agriculturalvehicle 10 on the road 115 is based on an ambient temperature of 25° C.The function expressing the speed restriction for the agriculturalvehicle 10 on the road 115 based on the load on the axle of the vehicle10 may be represented as a graph such as a line (e.g., a curve), atable, a diagram, or any other information that expresses therecommended maximal speed of the vehicle 10 based on the load on theaxle of the vehicle 10.

In this example, the speed restriction for the agricultural vehicle 10on the road 115 if an enhanced-roading feature (e.g., the lateral loaddistribution mechanism 100 or the wider and/or shorter traction lugs 58₁-58 _(T)) of the track system 16 _(i) was omitted but the track system16 _(i) was otherwise identical is represented by a function denoted“speed restriction without enhanced-roading feature”. This can beestablished by omitting the enhanced-roading feature (e.g., the lateralload distribution mechanism 100 or the wider and/or shorter tractionlugs 58 ₁-58 _(T)) of the track system 16 _(i) but keeping the tracksystem 16 _(i) otherwise identical. For instance, in embodiments inwhich the bottom track-contacting areas 146 of laterally-adjacent onesof the idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ are verticallymovable relative to one another (e.g., as described in section 1 above),this enhanced-roading feature may be omitted by precluding the bottomtrack-contacting areas 146 of the laterally-adjacent ones of the idlerwheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ from vertically moving relativeto one another. For example, in embodiments in which the lateral loaddistribution mechanism 100 allows the roll motion of laterally-adjacentones of the idler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ about theroll axis 164, this enhanced-roading feature may be omitted byprecluding the roll motion of the laterally-adjacent ones of the idlerwheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ about the roll axis 164 (e.g.,by removing, blocking or otherwise disabling a pivot enabling the rollmotion of the laterally-adjacent ones of the idler wheels 23 ₁, 23 ₂, 26₁, 26 ₂, 28 ₁-28 ₄ about the roll axis 164). This may be done in thetrack system 16 _(i) or by replacing the track system 16 _(i) with anidentical track system in which the enhanced-roading feature is omitted.

As shown in the chart, in this example, the speed restriction for theagricultural vehicle 10 on the road 115 may be laxer, i.e., theagricultural vehicle 10 may be authorized to travel faster on the road115, with the enhanced-roading feature. That is, the speed restrictionfor the agricultural vehicle 10 on the road 115 with theenhanced-roading feature may be defined in a zone SRZ of the chart thatis higher than the speed restriction without the enhanced-roadingfeature.

For example, in some embodiments, a ratio of (i) the speed restrictionfor the agricultural vehicle 10 on the road 115 with theenhanced-roading feature (e.g., the lateral load distribution mechanism100 or the wider and/or shorter traction lugs 58 ₁-58 _(T)) of the tracksystem 16 _(i) over (ii) the speed restriction for the agriculturalvehicle 10 on the road 115 if the enhanced-roading feature of the tracksystem 16 _(i) was omitted but the track system 16 _(i) was otherwiseidentical may be at least 1.10, in some cases at least 1.15, in somecases at least 1.20, in some cases at least 1.25, in some cases at least1.30, in some cases at least 1.45, and in some cases even more (e.g., atleast 1.50 or more). This ratio may have any other suitable value inother embodiments.

For instance, in some embodiments, when the load at the axle of thevehicle 10 is at least 40000 lbs, the ratio of (i) the speed restrictionfor the agricultural vehicle 10 on the road 115 with theenhanced-roading feature (e.g., the lateral load distribution mechanism100 or the wider and/or shorter traction lugs 58 ₁-58 _(T)) of the tracksystem 16 _(i) over (ii) the speed restriction for the agriculturalvehicle 10 on the road 115 if the enhanced-roading feature of the tracksystem 16 _(i) was omitted but the track system 16 _(i) was otherwiseidentical may be at least 1.10, in some cases at least 1.15, in somecases at least 1.20, in some cases at least 1.25, in some cases at least1.30, and in some cases even more (e.g., at least 1.40 or more). Thisratio may have any other suitable value in other embodiments.

FIGS. 44 to 48 show examples of subzones SZ₁-SZ₅ of the zone SRZ of thechart in which the speed restriction for the agricultural vehicle 10 onthe road 115 with the enhanced-roading feature can be defined in variousembodiments, where the agricultural vehicle 10 may be authorized totravel increasingly faster on the road 115.

As an example, in embodiments in which the lateral load distributionmechanism 100 allows the roll motion of laterally-adjacent ones of theidler wheels 23 ₁, 23 ₂, 26 ₁, 26 ₂, 28 ₁-28 ₄ about the roll axis 164,the speed restriction for the agricultural vehicle 10 on the road 115may be as defined as shown in FIG. 49.

In view of the enhanced-roading feature of the track system 16 _(i), theagricultural vehicle 10 may thus be authorized to travel faster on theroad 115. Notably, the track system 16 _(i) may be homologated to allowthe agricultural vehicle 10 to travel faster on the road 115. That is,the provider of the track system 16 _(i) may officially authorize theagricultural vehicle 10 to travel faster on the road 115, including byconveying the speed restriction for the agricultural vehicle 10 on theroad 115 that is more lax. For example, in some embodiments, theprovider of the track system 16 _(i) may honor a warranty for the tracksystem 16 _(i) according to the speed restriction for the agriculturalvehicle 10 on the road 115 that is more lax.

The speed restriction for the agricultural vehicle 10 on the road 115may be conveyed by the provider of the track system 16 _(i) in anysuitable way in various embodiments. For example, in some embodiments,the speed restriction for the agricultural vehicle 10 on the road 115may be conveyed by a tangible medium. For instance, the tangible mediummay be a manual (e.g., user or operator manual) provided with the tracksystem 16 _(i) and/or the agricultural vehicle 10. The tangible mediummay be a printed medium (e.g., a paper copy) or a computer-readablestorage medium (e.g., a semiconductor memory (e.g., read-only memory(ROM) and/or random-access memory (RAM)), a magnetic storage medium, anoptical storage medium, and/or any other suitable type of memory). Insome embodiments, the speed restriction for the agricultural vehicle 10on the road 115 may be conveyed on an Internet webpage provided by theprovider of the track system 16 _(i). In some embodiments, the speedrestriction for the agricultural vehicle 10 on the road 115 may beconveyed on the user interface 70 of the operator cabin 20 (e.g., on agraphical user interface (GUI) of a display of the user interface 70).In some embodiments, the speed restriction for the agricultural vehicle10 on the road 115 may be conveyed in a memory accessed by a controllerof the agricultural vehicle 10 that controls operation of the vehicle 10(e.g., a powertrain controller such as an engine control unit (ECU) thatcontrols the powertrain 15 of the vehicle 10).

Although the agricultural vehicle 10 illustrated in FIG. 1 is anagricultural tractor comprising four track systems 16 ₁-16 ₄, differenttypes of agricultural vehicles configured differently (e.g., having adifferent number of track systems) may implement improvements based onprinciples disclosed herein.

For instance, with additional reference to FIG. 50, an agriculturalvehicle 510 may be provided comprising two track systems 516 ₁, 516 ₂rather than four (i.e., one track system 516 _(i) at each side of theagricultural vehicle 510). The agricultural vehicle 510 also comprises aframe 512, a prime mover 514, and an operator cabin 520 and can beequipped with the work implement 18 to perform agricultural work. Eachtrack system 516 _(i) comprises a drive wheel 524 at a firstlongitudinal end portion of the track system 516 _(i), an idler wheel526 at a second longitudinal end portion of the track system 516 _(i)opposite to the first longitudinal end portion, and a plurality ofroller wheels 528 ₁-528 ₆ intermediate the drive wheel 524 and the idlerwheel 526. The track system 516 _(i) further comprises a track 522disposed around the wheels 524, 526, 528 ₁-528 ₆ and driven by the drivewheel 524. The track system 516 _(i) may implement the lateral loaddistribution mechanism 100 as described in section 1 above. Additionallyor alternatively, the track 522 may be configured in a manner similar tothe track 22 as described in section 2 above.

Furthermore, the work implement 18 that is drawn by the agriculturalvehicle 10 or the agricultural vehicle 510 may implement theimprovements disclosed herein. For instance, with additional referenceto FIG. 51, the work implement 18 may comprise a trailed vehicle 610comprising a frame 612, a body 613 (e.g., a container) and track systems616 ₁, 616 ₂. In this example, the trailed vehicle 610 is a harvestcart. In other examples, the trailed vehicle 610 may be a fertilizercart, a sprayer, a planter or any other suitable type of trailedvehicle. Each track system 616 _(i) of the trailed vehicle 610 comprisesfront (i.e., leading) idler wheels 623 ₁, 623 ₂ at a first longitudinalend portion of the track system 616 _(i), rear (i.e., trailing) idlerwheels 626 ₁, 626 ₂ at a second longitudinal end portion of the tracksystem 616 _(i) opposite the first longitudinal end portion, and aplurality of roller wheels 628 ₁-628 ₄ intermediate the front idlerwheels 623 ₁, 623 ₂ and the rear idler wheels 626 ₁, 626 ₂. The tracksystem 616 _(i) further comprises a track 622 disposed around the wheels626 ₁, 626 ₂, 626 ₁, 626 ₂, 628 ₁-628 ₄. The track system 616 _(i) mayimplement the lateral load distribution mechanism 100 as described insection 1 above. Additionally or alternatively, the track 622 may beconfigured in a manner similar to the track 22 as described in section 2above.

In this example, the trailed vehicle 610 is not motorized in that itdoes not comprise a prime mover for driving the track systems 616 ₁, 616₂. Rather, the trailed vehicle 610 is displaced by the agriculturalvehicle 10 or the agricultural vehicle 510 to which the trailed vehicle610 is attached. However, in some examples, the trailed vehicle 610 maybe motorized. That is, the trailed vehicle 610 may comprise a primemover for driving a drive wheel of each track system 616 _(i). Forexample, instead of comprising rear idler wheels 626 ₁, 626 ₂, the tracksystem 616 _(i) may comprise a drive wheel for driving the track 622.

In some examples of implementation, any feature of any embodimentdescribed herein may be used in combination with any feature of anyother embodiment described herein.

Certain additional elements that may be needed for operation of someembodiments have not been described or illustrated as they are assumedto be within the purview of those of ordinary skill in the art.Moreover, certain embodiments may be free of, may lack and/or mayfunction without any element that is not specifically disclosed herein.

Although various embodiments and examples have been presented, this wasfor the purpose of describing, but not limiting, the invention. Variousmodifications and enhancements will become apparent to those of ordinaryskill in the art and are within the scope of the invention, which isdefined by the appended claims.

1.-6. (canceled)
 7. A track for traction of a vehicle on a ground, thetrack being mountable around a track-engaging assembly including aplurality of track-contacting wheels configured to drive and guide thetrack around the track-engaging assembly, the track being elastomeric toflex around the track-engaging assembly, the track comprising: aground-engaging outer surface and an inner surface opposite to theground-engaging outer surface; and a plurality of traction projectionsprojecting from the ground-engaging outer surface, each tractionprojection being shaped to reduce potential for heat buildup within thetraction projection.
 8. The track of claim 7, wherein: the tractionprojection comprises a top surface configured to face the ground; and awidth of the top surface of the traction projection is greater than aheight of the traction projection.
 9. The track of claim 7, wherein: thetraction projection comprises a top surface configured to face theground; and a ratio of a width of the top surface of the tractionprojection over a width of the track is at least 0.1.
 10. The track ofclaim 7, wherein: the traction projection comprises a top surfaceconfigured to face the ground; and a ratio of a width of the top surfaceof the traction projection over a width of the track is at least 0.2.11. The track of claim 7, wherein a ratio of a height of the tractionprojection over a thickness of the track from the ground-engaging outersurface to the inner surface is no more than 1.2.
 12. The track of claim7, wherein a ratio of a height of the traction projection over athickness of the track from the ground-engaging outer surface to theinner surface is no more than 1.1.
 13. The track of claim 8, wherein aratio of the width of the top surface of the traction projection overthe height of the traction projection is at least 1.2.
 14. The track ofclaim 8, wherein a ratio of the width of the top surface of the tractionprojection over the height of the traction projection is at least 1.6.15. The track of claim 8, wherein a ratio of the width of the topsurface of the traction projection over the height of the tractionprojection is at least
 2. 16. A track for traction of a vehicle on aground, the track being mountable around a track-engaging assemblyincluding a plurality of track-contacting wheels configured to drive andguide the track around the track-engaging assembly, the track beingelastomeric to flex around the track-engaging assembly, the trackcomprising: a ground-engaging outer surface and an inner surfaceopposite to the ground-engaging outer surface; and a plurality oftraction projections projecting from the ground-engaging outer surface,each traction projection comprising a top surface configured to face theground, a width of the top surface of the traction projection beinggreater than a height of the traction projection.
 17. The track of claim16, wherein a ratio of the width of the top surface of the tractionprojection over the height of the traction projection is at least 1.2.18. The track of claim 16, wherein a ratio of the width of the topsurface of the traction projection over the height of the tractionprojection is at least 1.6.
 19. The track of claim X9, wherein a ratioof the width of the top surface of the traction projection over theheight of the traction projection is at least
 2. 20. A track fortraction of a vehicle on a ground, the track being mountable around atrack-engaging assembly including a plurality of track-contacting wheelsconfigured to drive and guide the track around the track-engagingassembly, the track being elastomeric to flex around the track-engagingassembly, the track comprising: a ground-engaging outer surface and aninner surface opposite to the ground-engaging outer surface; and aplurality of traction projections projecting from the ground-engagingouter surface; wherein a ratio of a height of each traction projectionover a thickness of the track from the ground-engaging outer surface tothe inner surface is no more than 1.2.